Two-way communications headsets are in common use in many types of vehicles and with various large pieces of machinery, especially vehicles and machinery that create a high noise environment during operation such that necessary two-way communications with the driver, operator or pilot would be impaired without such headsets. Examples of such noisy environments include airplane cockpits, driver's compartments in commercial trucks and tractors, operator cabins in cranes and tunnel boring machines, and crew compartments in tanks and other military vehicles. It is commonplace for such vehicles and machinery to incorporate an intercom system providing one or more connection points to which such headsets are coupled. Such intercoms typically cooperate with multiple ones of such headsets to enable personnel within or in the immediate vicinity of such vehicles to communicate with each other, and such intercoms typically incorporate long-range wireless transceivers enabling personnel to use such headsets in communicating with other personnel at a distance.
It has recently become increasingly desired to further enable such headsets to be coupled to portable audio devices that personnel may carry with them, in addition to being able to be coupled to an intercom system of a vehicle or large piece of machinery. Therefore, it has become desirable to enable the simultaneous coupling of a headset to both an intercom system and a personal audio device in a manner that provides a high degree of ease of use of such a combination, and avoids electrical incompatibility problems due to changes in a headset's operating state between being coupled to and uncoupled from an intercom system.
It has also become increasingly difficult to accommodate variances in the electrical characteristics encountered in headset connections provided by such intercom systems and/or long-range wireless transceivers (i.e., radios). Despite the existence of some industry and government standardization in some areas in which intercoms or radios are used, increasing complexities brought about by the addition of new features and increasing acceptance of end users making modifications have brought about a degree of ambiguity in expected characteristics and behavior. Thus, determining whether a connection to an intercom or radio has been made has been rendered more difficult, as well as determining whether that intercom or radio is active at any given time.
Further, there continues to be a desire to provide both operator convenience and conservation of power in headsets, as well as in other forms of personal audio device. Pushbutton power switches continue to be more sought-after than more traditional toggle-type power switches. However, difficulties have been encountered in providing a pushbutton power switch that does not also require the use of a combination of electronic components that continuously drain the limited power source (e.g., a battery) of a personal audio device (e.g., a headset).